Bulletin - United States National Museum - Smithsonian Institution

102 BULLETIN 91, UNITED STATES NATIONAL MUSEUM.
No. 950). The type has lost the early nuclear whorls, the last one
only remaining. In addition to that it has a little more than 10
post-nuclear whorls, and measures: Length, 9.5 mm.; diameter,
3.1 mm.
TR1PHORIS SHEPSTONENSIS Smith.
Cat. No. 186804, U.S.N.M., four specimens from Port Alfred
(Coll. No. 170). Cat. No. 227716, U.S.N.M., six specimens from
the same locality (Coll. No. 811). Cat. No. 250351, U.S.N.M., another
specimen from Port Alfred (Coll. No. 1224).
TRIPHORlS MILDA, new species.
Plate 11, fig-. 3.
Shell elongate-conic, light brown. Nuclear whorls decollated.
Post-nuclear whorls tabulatedly shouldered at the summit, flattened,
marked by three strong, tuberculated spiral cords, of which the first
is at the summit, the second halfway between this and the last, the
latter being about as far above the suture as it is distant from the
median. In addition to the spiral cords the whorls are marked by
rather strong, broad, almost vertical axial ribs, of which 14 occur
upon the first and second, 16 upon the third, 20 upon the fourth and
fifth, 22 upon the sixth to ninth, 26 upon the tenth, 24 upon the
eleventh, 26 upon the twelfth, and 28 upon the thirteenth and the
penultimate turn. The junctions of the axial ribs and the spiral
cords form strong tubercles, of which those on the first cord are
truncated anteriorly, forming a decidedly channeled, crenulated
suture. These tubercles are of oval outline, having then long axis
parallel with the ribs. The tubercles of the median cord are almost
rounded, truncated posteriorly, and slope gently anteriorly. Those
of the supra-sutural cord are smaller than the rest and a little more
strongly truncated posteriorly, sloping abruptly anteriorly. The
spaces inclosed between the axial ribs and peripheral cords are well
rounded, strongly impressed pits. Sutures strongly channeled, showing
a portion of the first basal cord. Periphery of the last whorl
marked by a sulcus, which is crossed by the continuations of the axial
ribs and is about as wide as the sulcus on the spire. Base well rounded,
marked by three strong spiral cords, which divide the posterior
half of the base, that is, the space between the peripheral sulcus
and the insertion of the columella, into equal portions. These
three cords become diminished in strength in regular sequence from
the one adjacent to the periphery to the one on the columella. The
entire surface of the shell is marked by exceedingly fine lines of
growth and microscopic spiral striations. Aperture strongly chan-
neled anteriorly, less so posteriorly; junction of the basal and outer
lip forming a decided angle that projects as a claw-like element;
outer lip thin, showing the external sculpture within; columella short,
stout, curved, marked by a thick callus which extends over the
parietal wall and renders the peritreme complete.